The present invention relates to a method for providing a toughening treatment for metallic material by making use of transformation super-plastic phenomena.
Heretofore, heat treatment of metallic materials has been conducted in various ways for the purpose of enhancing the mechanical strength and improving toughness of metallic materials including steel. However, most of the methods were heat treatments at a raised temperature extending over a long period of time because they were aimed to disperse and separate non-metal interstitial substances such as carbides.